基于Mn3+浓度和形貌控制的高性能LiNi0.5Mn1.5O4正极材料

为了改善高电压镍锰酸锂(LiNi_(0.5)Mn_(1.5)O_4)材料的电化学性能,提出利用退火热处理过程调控Mn~(3+)含量和材料形貌来制备LiNi_(0.5)Mn_(1.5)O_4正极材料。LiNi_(0.5)Mn_(1.5)O_4材料的电性能是材料结构、形貌等多因素影响的结果。退火热处理有助于Mn~(3+)氧化成Mn~(4+),实现Mn~(3+)含量调控。退火后材料的空间结构由Fd3m向P4_332转变,且具有微米级多面体形貌,有效提高了循环稳定性和放电平台。研究表明:700℃退火保温15 h合成的材料在20 C下具有118 mAh·g~(-1)放电比容量,循环100次容量保持率提高到92.8%。因此,通过优化Mn~(3+)含量、控制材料形貌可以实现高性能LiNi_(0.5)Mn_(1.5)O_4材料制备。

High-Performance LiNi0.5Mn1.5O4 Cathode Materials Based on Mn3+ Concentration and Morphology Control

In order to improve the electrochemical properties of high-voltage LiNi0.5Mn1.5O4 materials, it is proposed to prepare the LiNi0.5Mn1.5O4 cathode materials by adjusting the Mn3+ concentration and material morphology through annealing. The electrical properties of LiNi0.5Mn1.5O4 are influenced by many factors such as the structure and morphology of the material. Annealing heat treatment is helpful for the oxidation of Mn3+ to Mn4+, so that the control of Mn3+ concentration can be realized. After annealing, the spatial structure of the material is transformed from Fd3m to P4332, and has a micro-scale polyhedron morphology, which effectively improves the cycling stability and discharge-voltage platform. The results show that the material annealed at 700 ºC for 15 h has a specific discharge capacity of 118 mAh.g-1 at 20 C, and the capacity retention rate is increased to 92.8% after 100 cycles. Therefore, high-performance LiNi0.5Mn1.5O4 materials can be prepared by optimizing the Mn3+ concentration and controlling the material morphology.